Objective: To study the clinicopathologic characteristics and differential diagnosis of mammary myofibroblastoma. Methods: Nine cases of mammary myofibroblastoma diagnosed between 2006 and 2017 were collected from the Department of Pathology, Fudan University Shanghai Cancer Center. Clinical and histopathologic features of these nine cases were examined, immunohistochemical staining was performed, FISH analysis for the detection of FOXO1 gene was performed in one case, and follow-up data were also collected. Results: There were seven female and two male patients, with a mean age of 54 years, median age of 50 years (ranging from 40 to 83 years). Four lesions each were located in the left and right breast, and one was in the left subaxillary accessory breast tissue. Clinically, 8 patients presented with a breast mass, 3 of which accompanied with pain. All of the tumors were well-demarcated grossly with a mean diameter of 2.5 cm. Microscopically, there were no entrapped ductal or lobular structures within the tumor. Seven tumors were classic type, which were composed of bland-looking spindle neoplastic cells without mitoses, arranging in intersecting fascicles, and interrupted by thick hyalinized collagen bundles. One case was of epithelioid variant, demonstrating epithelioid neoplastic cells diffusely arranged or in cluster. The other one case was mixed spindle and epithelioid-cell type. Atypical tumor cells were observed in 3 cases. Immunohistochemically, tumor cells were diffusely positive for desmin (9/9) and CD34 (6/9), as well as ER (7/7), PR (6/6) and bcl-2 (3/3). SMA (4/7) and Calponin (1/2) were focally or partially positive in some cases. H-caldesmon (1/2) was weakly positive and epithelial markers were negative. Ki-67 proliferation index was low (<10%). There was no monoallelic loss of FOXO1/13q14 loci in the detected case according to FISH analysis. Follow-up data were available for all patients, and follow-up period ranged from 12 to 78 months. All patients remained well without recurrence. Conclusions Mammary myofibroblastoma is a rare benign mesenchymal tumor. In some circumstances, it may exhibit confusing morphologies, including some variants. The epithelioid variant of mammary myofibroblastoma might mimic invasive lobular carcinoma, leading to the diagnostic dilemmas and even misdiagnosis, especially in core needle biopsy specimen or frozen sections. Familiarity with the characteristics of this tumor is of great importance for accurate diagnosis and proper treatment.

Objective:To investigate the clinical value of the first multicolor fluorescence in situ hybridization (FISH) assay on multiple genes, and combined with 9p21 and 8q24 evaluation in the differential diagnosis of melanoma.Methods:Fifty-six melanomas and 36 benign melanocytic nevi diagnosed in Fudan University Shanghai Cancer Center from 2017 to 2019 were included. Each specimen was examined by first multicolor FISH assay targeting 6p25 (RREB1), 6q23 (MYB), 11q13 (CCND1) and CEP6, as well as 9p21 (CDKN2A) and 8q24 (MYC). The results of FISH assay in all cases were recorded according to Gerami′s criteria. Basing on the sensitivity and specificity of the first FISH assay, the refinement of diagnosis by adding combined 9p21 and 8q24 probes was further evaluated, as well as their association with different clinicopathological features.Results:In 86 cases, the FISH signals were adequate for analysis. Of the 56 melanoma cases, 52 cases were adequate for analysis; 36 cases (69.2%) were positive in the first FISH assay. The most frequent chromosomal anomaly was gain of RREB1 (30/52, 57.7%), followed by gain of CCND1 (20/52, 38.5%), loss of MYB relative to CEP6 (18/52, 34.6%) and gain of RREB1 relative to CEP6 (17/52, 32.7%). The frequency of homozygous deletions in 9p21 was 15.4% (8/52) and gain of 8q24 was 36.5% (19/52). Among the 36 melanocytic nevi cases, FISH results could be accurately evaluated in 34 cases, and none showed a positive result in the first FISH assay or 9p21 and 8q24 FISH analysis. Compared with the first FISH assay, the sensitivity of combination with 9p21 and 8q24 FISH analysis increased from 69.2% to 76.9% (40/52) and the specificity remained 100.0%. Statistical data showed that the rates of FISH positivity in patients with acral-lentiginious melanoma and nodual melanoma subtypes were higher than that in patients with superficial spreading melanoma and lentigo maligna melanoma subtypes, and patients with Breslow thickness>2.0 mm had higher positive FISH frequency than patients with Breslow thickness ≤2.0 mm.Conclusion:Multisite FISH analysis is a highly effective ancillary tool for the differentiation of unequivocal malignant from benign melanocytic lesions. By combining the first FISH assay with CDKN2A and MYC assay, the clinical utility of FISH analysis is further optimized in differential diagnosis of melanoma. Patients with Breslow thickness>2.0 mm, or acral-lentiginious melanoma and nodual melanoma subtypes tend to have higher FISH positivity. There remains a need to further explore the ancillary value of FISH analysis in diagnosis of ambiguous lesions.

Objective:To investigate MAML2 gene rearrangement, gene fusion patterns, and the clinicopathological characteristics of primary pulmonary mucoepidermoid carcinoma (PMEC).Methods:Forty-six cases of primary PMEC from Fudan University Zhongshan Hospital and Fudan University Shanghai Cancer Center between 2017 and 2020 were collected. MAML2 gene rearrangement in all cases was detected by fluorescence in situ hybridization (FISH). In 20 cases, MAML2 fusion patterns were detected by targeted RNA sequencing (RNAseq). The relationship between MAML2 gene rearrangement, fusion patterns, clinicopathological characteristics, and prognosis was analyzed.Results:The average age of PMEC patients was 41 years (range 15-71 years); the ratio of male to female was about 1.1 ∶ 1.0. Most PMECs were low grade in histopathology with an early clinical stage (stageⅠ-Ⅱ).The overall positive rate of MAML2 gene rearrangement detected by FISH was about 80.4% (37/46), and the rate was higher in low-grade PMEC (91.7%, 33/36). Of the 20 cases detected by RNAseq, all the 19 FISH positive cases showed gene fusion, mainly CRTC1-MAML2 fusion (16/19), the other three cases showed CRTC3-MAML2 fusion (3/19), the break point of all the fusion patterns was CRTC1/3 (exon 1)-MAML2 (exon 2); No gene fusion was detected in the single FISH negative case; Compared with the MAML2 FISH negative patients, the PMECs carrying CRTC1-MAML2 fusion were more commonly found in patients age ≤ 40 years, maximum tumor diameter ≤ 2 cm, low histopathological grade and early clinical stage (all P<0.05); The three PMECs carrying CRTC3-MAML2 fusion gene were all female with early clinical stage; Univariate analysis showed that MAML2 gene rearrangement/fusion, onset age ≤ 40 years old, smaller tumor size, low histopathological grade, early clinical stage, no metastasis at diagnosis and surgical treatment were significantly correlated with overall survival ( P<0.05), but Cox regression analysis suggested that none of the above indicators were the independent prognostic factors for the survival of PMEC. Conclusions:The high incidence of MAML2 gene rearrangement in PMEC suggests that it is an important molecular diagnostic marker of PMEC. RNAseq confirms that CRTC1/3-MAML2 is the main fusion pattern in PMEC, suggesting that MAML2 fusion transcription may be an important driving factor of PMEC. MAML2 rearrangement/fusion and related clinicopathological characteristics are associated with good prognosis.

Objective: To investigate clinicopathological, cytogenetic features and differential diagnoses of high grade endometrial stromal sarcoma (HGESS) with BCOR gene rearrangement. Methods: Five cases of HGESS with BCOR rearrangement were collected from consultant files (2016-2018) at Fudan University Shanghai Cancer Center. Interphase FISH was performed using a dual color break-apart probe. The clinical data, histologic features and immunohistochemical findings were reviewed. Results: All 5 cases occurred in adult women with a median age of 48 (range, 45-55) years. Abdominal pain and abnormal vaginal bleeding were the most common symptoms. Microscopically, the tumors showed mainly tongue-like and/or intersecting myometrial invasion. Stromal myxoid matrix and/or collagen plaques were prominent in all the cases. Most tumors consisted of uniform, haphazard fascicles of short spindle cells with mild to moderate nuclear atypia. Mitotic figures and necrosis were easily identified. Significant nuclear pleomorphism was not seen. Most tumors were rich in thick-walled small vessels. Prominent perivascular tumor cell whorling seen in conventional low-grade endometrial stromal sarcoma was not seen. All tumors expressed CD10 with only focal or absent desmin, SMA and/or h-caldesmon staining. ER or PR expression was seen in 4 tumors and 1 tumor showed both marker expression. Diffuse cyclin D1 was present in 2 tumors. BCOR immunoreactivity was present with strong staining in 3 cases and moderate staining in 1 case respectively. Ki-67 index ranged from 10% to 30%. Fluorescence in situ hybridization confirmed chromosomal aberration of BCOR gene in all tumors, that were previously diagnosed as myxoid leiomyosarcoma (2 cases), spindle cell uterine sarcoma (2 cases) and low-grade endometrial stromal sarcoma (1 case). Limited follow-up information revealed that 3/5 patients developed tumor recurrence, metastasis or death within one year. Conclusion BCOR rearranged HGESS has distinct morphological features and aggressive clinical behavior. In the presence of significant overlapping morphologic features between BCOR rearranged HGESS and other myxoid uterine mesenchymal tumors, especially myxoid leiomyosarcoma, molecular analysis is essential for accurate diagnoses.

Objective: To investigate the role of JAZF1 gene rearrangement in the diagnosis and differential diagnosis of endometrial stromal sarcomas by fluorescence in situ hybridization (FISH). Methods: JAZF1 gene rearrangement was analyzed by FISH in 129 cases of ESS diagnosed from January 2008 to December 2016 including 105 cases of low-grade endometrial stromal sarcoma (LG-ESS), 21 cases of high-grade endometrial stromal sarcoma (HG-ESS) and 3 cases of undifferentiated uterine sarcoma (UUS). Sixteen cases of the related tumours in uterus were also collected as control group. The results were compared with our previous studies of JAZF1/JJAZ1 fusion gene in ESS by RT-PCR. Results: Detection of JAZF1 gene rearrangement by FISH was successfully analyzed in 144 cases. JAZF1 gene alteration was detected in 63 cases, all of which were LG-ESS, with an overall positivity of 60.6% (63/104), while no JAZF1 gene rearrangement was found in all other cases. JAZF1 gene rearrangement was present in LG-ESS with classic histology (69.3%, 52/75), smooth muscle differentiation (2/10), sex cord-like differentiation (4/5), fibromyxoid change (1/5), clear cell change (0/1), skeletal muscle differentiation (0/1), and schwannoma-like palisading pattern (0/1). The different components in all the cases of LG-ESS with variant histology had the clonal origin, with or without JAZF1 gene alteration. Compared to the results of JAZF1/JJAZ1 fusion gene by RT-PCR, the positive rate of JAZF1 gene rearrangement in LG-ESS by FISH (61.9%, 26/42) was significantly higher than that of RT-PCR (30.0%, 12/40; P<0.01). Conclusions JAZF1 gene rearrangement is present only in LG-ESS, but not in HG-ESS, UUS or other related tumours in uterus. The frequency of JAZF1 gene rearrangement varies between classic LG-ESS and different morphologic variants. It is frequently, but not consistently, present in classic LG-ESS and less often positive in variant cases. The results of JAZF1 gene alterations in LG-ESS with different morphologic variants support the contention that the endometrial stromal and their variant morphologic components have the same clonal origin. Detection of JAZF1 gene rearrangement by FISH is very useful for the diagnosis and differential diagnosis of ESS.

Objective To investigate clinicopathological, cytogenetic features and differential diagnoses of high grade endometrial stromal sarcoma(HGESS) with BCOR gene rearrangement. Methods Five cases of HGESS with BCOR rearrangement were collected from consultant files (2016-2018) at Fudan University Shanghai Cancer Center. Interphase FISH was performed using a dual color break‐apart probe. The clinical data, histologic features and immunohistochemical findings were reviewed. Results All 5 cases occurred in adult women with a median age of 48 (range, 45-55) years. Abdominal pain and abnormal vaginal bleeding were the most common symptoms. Microscopically, the tumors showed mainly tongue‐like and/or intersecting myometrial invasion. Stromal myxoid matrix and/or collagen plaques were prominent in all the cases. Most tumors consisted of uniform, haphazard fascicles of short spindle cells with mild to moderate nuclear atypia. Mitotic figures and necrosis were easily identified. Significant nuclear pleomorphism was not seen. Most tumors were rich in thick‐walled small vessels. Prominent perivascular tumor cell whorling seen in conventional low‐grade endometrial stromal sarcoma was not seen. All tumors expressed CD10 with only focal or absent desmin, SMA and/or h‐caldesmon staining. ER or PR expression was seen in 4 tumors and 1 tumor showed both marker expression. Diffuse cyclin D1 was present in 2 tumors. BCOR immunoreactivity was present with strong staining in 3 cases and moderate staining in 1 case respectively. Ki‐67 index ranged from 10% to 30%. Fluorescence in situ hybridization confirmed chromosomal aberration of BCOR gene in all tumors, that were previously diagnosed as myxoid leiomyosarcoma (2 cases), spindle cell uterine sarcoma (2 cases) and low‐grade endometrial stromal sarcoma (1 case). Limited follow‐up information revealed that 3/5 patients developed tumor recurrence, metastasis or death within one year. Conclusion BCOR rearranged HGESS has distinct morphological features and aggressive clinical behavior. In the presence of significant overlapping morphologic features between BCOR rearranged HGESS and other myxoid uterine mesenchymal tumors, especially myxoid leiomyosarcoma, molecular analysis is essential for accurate diagnoses.

Objective: To investigate the clinicopathologic and genetic features, pathologic diagnosis and differential diagnosis of angiofibroma of soft tissue(AFST). Methods: The clinicopathologic characteristics of 24 cases diagnosed at Fudan University Shanghai Cancer Center from 2011 to 2017 were analyzed; immunohistochemical staining and interphase fluorescence in situ hybridization (FISH) were performed, and the literatures were also reviewed. Results: There were 15 male and 9 female (male∶female=1.7∶1.0) patients with age of onset ranging from 8 to 68 years (mean, 45 years). Fourteen cases occurred in extremities, including upper limbs (n=3) and lower limbs (n=11); seven cases were in the trunk, and 1 case each was in the temporal region, retroperitoneum and liver, respectively. Clinically, the tumors usually presented as a slowly growing painless mass. Tumor sizes ranged from 0.8 to 14 cm (mean 4.6 cm). Microscopically, most lesions were well-circumscribed, with fibrous capsules. Few cases infiltrated the surrounding fibrofatty tissue focally. The tumors were mainly composed of sparse short spindle cells and numerous small, branching, thin-walled blood vessels distributed in amyxoid, fibromyxoid or collagenous matrix, often accompanied by medium-sized, round or irregular and ecstatic vessels at the tumor periphery.By immunohistochemistry, all tested cases expressed vimentin (5/5), and showed variable positivity for EMA (2/4), ER (1/2), PR (2/3), α-SMA (1/18)and desmin (1/10). Ki-67 proliferation index were all less than 5%. CD34, CD31 and ERG staining clearly outlined the contours of blood vessels in the stroma. Four cases were tested for NCOA2 gene rearrangement by FISH, of which three were positive. Follow-up data was available in 17 patients (range, 3 to 69 months; mean, 30 months) were all free of disease. Conclusions Soft tissue angiofibroma is a benign fibroblastic neoplasm characterized by a prominent and complex vasculature set in a myxoid-to-collagenous stroma, and cytogenetically a distinctive NCOA2 gene rearrangement. Caution should be exercised for the possibility of potentially misinterpretation of AFST as vascular tumors and other myxoid soft tissue tumors.

Objective:To investigate the clinicopathological features, immunophenotype, diagnosis and differential diagnosis of SRF-rearranged cellular perivascular myoid tumor.Methods:Two cases of SRF-rearranged cellular perivascular myoid tumor diagnosed in the Department of Pathology, Fudan University Shanghai Cancer Center from October 2021 to March 2022 were collected. Immunohistochemical staining, fluorescence in-situ hybridization (FISH) and next-generation sequencing (NGS) were performed, and the literature was reviewed.Results:Case 1, a 3-month-old boy presented with a painless tumor of the scalp, measuring about 2 cm in diameter. Case 2, a 3-year-old girl complained with a painless tumor of the knee, measuring approximately 1.5 cm in diameter. Microscopically, the tumor had a clear boundary and showed multinodular growth. The tumor was mainly composed of spindle cells arranged in long intersecting fascicles associated with thin, slit-like or branching ectatic vessels, focally forming hemangiopericytoma-like appearance. The tumor cells were abundant, but there was no obvious atypia. Mitotic figures (3-4/10 HPF) were noted. H-caldesmon and SMA were positive in both cases. Case 1 showed diffuse and strong positivity for Desmin, and focally for CKpan. Ki-67 proliferation index was 20% and 30%, respectively. FISH displayed NCOA2 gene translocation in case 1 and the RELA gene translocation in case 2. NGS detected the SRF-NCOA2 gene fusion in case 1 and the SRF-RELA gene fusion in case 2. Both patients underwent local excisions. During the follow-up of 5-14 months, case 1 had no local recurrence, while case 2 developed local recurrence 1 year post operatively.Conclusions:SRF-rearranged cellular perivascular myoid tumor is a novel variant of perivascular cell tumor, which tends to occur in children and adolescents. The tumor forms a broad morphologic spectrum ranging from a pericytic pattern to a myoid pattern, and include hybrid tumors with a mixture of pericytic and myoid patterns. Due to its diffuse hypercellularity and increased mitotic figures and smooth muscle-like immunophenotype, the tumor is easy to be misdiagnosed as myogenic sarcomas. The tumor usually pursues a benign clinical course and rare cases may locally recur.

Objective To study the cytomorphologic features of anaplastic lymphoma kinase ( ALK )-rearranged pulmonary adenocarcinoma.Methods The morphologic features in 153 pulmonary adenocarcinoma cytology specimens encountered during the period from September, 2011 to April, 2015 in Shanghai Cancer Hospital were retrospectively reviewed.Fluorescence in-situ hybridization ( FISH) and/or immunohistochemistry ( Ventana D5F3) for ALK gene rearrangement were carried out.The samples studied included 34 pleural effusion specimens, 40 endobronchial ultrasound-guided transbronchial needle aspirates ( EBUS-TBNA) and 79 fine needle aspirates of palpable masses on body surface.Results Thirty-nine cases (25.5%) of ALK-rearranged samples were identified by FISH and/or immunohistochemistry, including 3 cases diagnosed by FISH and 36 cases by both technologies.The median age of the ALK-positive group was 50 years, significantly younger than that of the ALK-negative group (60 years old,P=0.002) .Only 4 of the ALK-positive patients were smokers, which was significantly less than that of the ALK-negative group (P<0.01).In ALK-positive group, 3 cases showed cribriform pattern with prominent nucleoli, 3 cases showed cribriform pattern with mucin-rich cells and 8 cases showed extracellular mucus with mucin-rich cells.The above cytomorphologic patterns were significantly less common in ALK-negative tumors ( P <0.01 ) . Conclusions ALK-rearranged lung adenocarcinoma is associated with certain distinctive morphologic patterns, including cribriform architecture, presence of prominent nucleoli, mucin-rich cells and extracellular mucus, which can be observed in cytology specimens ( including conventional smears and cell block sections) .These findings, when combined with clinical features, may give clues to detection of ALK-positive cases.

OBJECTIVETo study the cytomorphologic features of anaplastic lymphoma kinase (ALK)-rearranged pulmonary adenocarcinoma.

METHODSThe morphologic features in 153 pulmonary adenocarcinoma cytology specimens encountered during the period from September, 2011 to April, 2015 in Shanghai Cancer Hospital were retrospectively reviewed. Fluorescence in-situ hybridization (FISH) and/or immunohistochemistry (Ventana D5F3) for ALK gene rearrangement were carried out. The samples studied included 34 pleural effusion specimens, 40 endobronchial ultrasound-guided transbronchial needle aspirates (EBUS-TBNA) and 79 fine needle aspirates of palpable masses on body surface.

RESULTSThirty-nine cases (25.5%) of ALK-rearranged samples were identified by FISH and/or immunohistochemistry, including 3 cases diagnosed by FISH and 36 cases by both technologies. The median age of the ALK-positive group was 50 years, significantly younger than that of the ALK-negative group (60 years old, P = 0.002). Only 4 of the ALK-positive patients were smokers, which was significantly less than that of the ALK-negative group (P < 0.01). In ALK-positive group, 3 cases showed cribriform pattern with prominent nucleoli, 3 cases showed cribriform pattern with mucin-rich cells and 8 cases showed extracellular mucus with mucin-rich cells. The above cytomorphologic patterns were significantly less common in ALK-negative tumors (P < 0.01).

CONCLUSIONSALK-rearranged lung adenocarcinoma is associated with certain distinctive morphologic patterns, including cribriform architecture, presence of prominent nucleoli, mucin-rich cells and extracellular mucus, which can be observed in cytology specimens (including conventional smears and cell block sections). These findings, when combined with clinical features, may give clues to detection of ALK-positive cases.

Adenocarcinoma ; genetics ; pathology ; Biopsy, Fine-Needle ; China ; Gene Rearrangement ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Lung Neoplasms ; genetics ; pathology ; Receptor Protein-Tyrosine Kinases ; genetics ; Retrospective Studies